Cadence detection system and cadence sensor therefor

ABSTRACT

A cadence detection system may include a cadence sensor and an exercise device, such as a stationary bike, an indoor cycle trainer, a bicycle trainer, a rowing machine, a stair stepping machine, or the like. In operation, the cadence sensor detects movement of at least one component of the drive train of the exercise device during operation thereof, which in turn, may be utilized for calculating the cadence of the exercise device.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Provisional Application No. 61/512,858, filed Jul. 28, 2011, which is hereby incorporated by reference.

BACKGROUND

Cycling is a very popular activity for both recreational riders and racing enthusiasts alike. Professional cyclists and triathletes are earning large sums of money through races, sponsorships, and advertisements. Moreover, cycling provides many health benefits for average riders in that it strengthens various muscle groups along with providing aerobic and anaerobic exercise to the user. Furthermore, physicians and physical therapists are turning to stationary cycle devices to rehabilitate patients from automobile, athletic, or work-related injuries. Because of this, there is a demand for indoor, stationary exercise trainers that simulate actual outdoor riding so that professional and recreational cyclists may train or exercise regardless of the weather, and that patients can rehabilitate injuries in the presence of their physicians and physical therapists.

Various stationary cycle trainers have been presented to address this need. Conventional stationary cycle trainers simulate the characteristics of outdoor training by applying a variable resistance device to provide resistance against the pedaling of the rider. The variable resistance device mimics the resistances a rider would face during actual outdoor training such as wind resistance, rolling resistance, and resistances due to riding over varying terrain. The variable resistance devices may be of the wind, fluid, or roller type. Recently, the use of “eddy current” trainers has achieved widespread use due to their ability to simulate the resistance (loads) felt by riders during actual riding.

Further advancements in “eddy current” trainers have allowed for the monitoring and evaluation of the rider's or patient's performance during the exercise session. These trainers generally use a microprocessor/sensor arrangement to calculate several session parameters, such as heart rate, energy exertion, time elapsed, distance and cadence. Currently available sensors for sensing cadence include a reed switch or hall effect sensor mounted directly to the cycle frame, and a magnet base mounted for rotation with one of the cycle crank arms or chain rings. Such cadence sensors generate a pulse signal to be transmitted to the microprocessor each time the magnet base passes the reed switch or hall effect sensor.

The microprocessor of the eddy current trainer is also connected to an electric drive circuit that energizes the electromagnets of the variable resistance device at predetermined times and power levels in order to simulate changes in terrain. An eddy current trainer that uses electromagnets to simulate real life bicycling road conditions, and that uses a microprocessor to evaluate the user's performance as stated above, is currently sold under the trademark COMPUTRAINER by Racermate, Inc., Seattle, Wash.

SUMMARY

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

In accordance with aspects of the present disclosure, a cadence detection system is provided for use during exercise. The system comprises an exercise device having a moveable drivetrain configured to provide a cadence. The moveable drivetrain includes a target surface. The system also includes an optical sensor placed on a surface separate from the exercise device and positioned in optical view of the target surface of the moveable drivetrain. In some embodiments, the optical sensor includes an emitter configured to generate an optical signal for output and a detector configured to detect the optical signal after reflection off of the target surface, wherein the optical sensor is configured to generate an electrical signal based on the detected optical signal. The system also includes a computing device configured to receive the electrical signal from the optical sensor and to calculate at least detected optical sensor signal instances received per unit of time.

In accordance with another aspect of the present disclosure, a cadence detection system is provided for use during exercise. The system includes at least two exercise devices having moveable drivetrains. Each device is configured to generate a unique cadence and the moveable drivetrains each includes a target surface. The system also includes an optical sensor associated with each exercise device and placed on a surface separate from the associated exercise device. Each optical sensor is positioned in optical view of the target surface of the respective moveable drivetrain. In some embodiments, each of the optical sensors includes an emitter configured to generate optical signals for output and a detector configured to detect the optical signals after reflection off of the respective target surface, and are configured to generate electrical signals based on the detected optical signals. The system also includes a computing device configured to receive the electrical signals from the optical sensors and to calculate at least detected optical sensor signal instances received per unit time.

In accordance with another aspect of the present disclosure, a method is provided for detecting cadence during stationary exercise. The method includes continuously emitting light from a light source having a nominal range, moving a component of a drivetrain into and out of the nominal range, detecting reflected light off of the component, and calculating cadence of the drivetrain.

DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a perspective view of one example of a cadence detection system formed in accordance with aspects of the present disclosure;

FIG. 2A is a partial elevational view of the cadence detection system of FIG. 1 depicting one example of a cadence sensor in cross section and a pedal of an associated stationary bike, indoor cycle trainer, bicycle trainer, or the like, positioned along a portion of its down stroke;

FIG. 2B is a partial elevational view of the cadence detection system of FIG. 1 depicting one example of a cadence sensor in cross section and a pedal of an associated stationary bike, indoor cycle trainer, bicycle trainer, or the like, positioned at the bottom of its down stroke;

FIG. 3 is a block diagram of one example of a sensor suitable for use in the cadence detection system of FIG. 1;

FIG. 4 is a block diagram of one example of a multi rider environment employing a centralized computing device;

FIG. 5 is a side elevational view of another example of a cadence detection system formed in accordance with aspects of the present disclosure;

FIG. 6 is a side elevational view of yet another example of a cadence detection system formed in accordance with aspects of the present disclosure;

FIG. 7 is a perspective view of still another example of a cadence detection system formed in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings where like numerals reference like elements is intended as a description of various embodiments of the disclosed subject matter and is not intended to represent the only embodiments. Each embodiment described in this disclosure is provided merely as an example or illustration and should not be construed as preferred or advantageous over other embodiments. The illustrative examples provided herein are not intended to be exhaustive or to limit the claimed subject matter to the precise forms disclosed. Similarly, any steps described herein may be interchangeable with other steps, or combinations of steps, in order to achieve the same or substantially similar result.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of exemplary embodiments of the present disclosure. It will be apparent to one skilled in the art, however, that many embodiments of the present disclosure may be practiced without some or all of the specific details. In some instances, well-known process steps have not been described in detail in order not to unnecessarily obscure various aspects of the present disclosure. Further, it will be appreciated that embodiments of the present disclosure may employ any combination of features described herein.

Referring now to FIG. 1, there is shown an exemplary embodiment of a cadence detection system, generally designated 20, formed in accordance with aspects of the present disclosure. Generally, the system 20 includes a cadence sensor 22 and an exercise device 24, such as a stationary bike, indoor cycle trainer, bicycle trainer, or the like. In the example depicted in FIG. 1, the exercise device 24 includes a pedal powered exercise device in the form of a bicycle 26 having pedal driven drivetrain 28 suitably mounted to an exercise apparatus or trainer 30. As will be described in more detail below, the cadence sensor 22 detects movement of at least one component of the drive train 28 during operation of the exercise device 24, which in turn, may be utilized for calculating the cadence of the exercise device 24.

Still referring to FIG. 1, the components of the cadence detection system 20 will now be described in more detail. As best shown in the embodiment of FIG. 1, the exercise device 24 may include a bicycle 26 operatively mounted to a trainer 30. The bicycle 26 in one embodiment includes a frame 34, a front fork 36 mounted to the front of the frame 34, and handlebars 38 mounted to an upper end of front fork 36. A front wheel 40 is mounted for rotation on front fork 36 in a conventional manner. Alternatively, the front wheel 40 may be omitted and the front fork 36 may be mounted onto a stationary mount. The bicycle 26 also includes a seat 42 and a driven rear wheel 46, which are mounted to the frame 34 rearwardly of the handlebars 38 and the front wheel 40.

The bicycle 26 further includes a drivetrain 28 to transmit power from the rider to the driven rear wheel 46. In that regard, the frame 34 further supports a crank set 50. The crank set 50 is operatively connected to the frame 34 via a spindle/bearing combination known as a bottom bracket (hidden in FIG. 1). The crank set 50 generally includes one or more chain rings 54 or front sprockets, a left hand crank arm 56 and a right hand crank arm (hidden in FIG. 1), a left hand pedal 58 mounted on a left-hand crank arm 56, and a right-hand pedal (hidden in FIG. 1) mounted on a right-hand crank arm. Rotation of the left-hand and right-hand pedals imparts rotation to a hub 60 of the rear wheel 46 via a chain and cogwheel or rear sprocket arrangement 64. The rotational speed, in revolutions per minute, of the crank set 50 or parts thereof, is typically referred to as “cadence.”

Still referring to FIG. 1, the training device 30, on which the bicycle 26 is mounted, may include a frame 70, a resistance generator 74, such as an eddy current brake, wind brake, fluid brake, etc., a shaft 76 and a flywheel 78. The frame 70 is formed of a U-shaped forward frame member 80 and a U-shaped rear frame member 82. The ends of the frame members 80 and 82 are pivotally joined at a pivot 84. The forward and rear U-shaped frame members 80 and 82 rotate with respect to each other around pivot 84. This rotational movement allows the frame 70 to be moved between a collapsed position (not shown) and an extended position (FIG. 1). In the collapsed position, the forward and rear frame members 80 and 82 lie adjacent to each other while in the extended position or the forward and rear members form an upside-down V, as illustrated in FIG. 1.

The rear end of the frame 34 of the bicycle 26 is mounted within the frame 70 of the training device 30 at the pivot point 84. When placed in the frame 70, the rotational axis of the rear wheel 46 as defined by the hub 60 is aligned with the pivot 84. The resistance generator 74 is mounted on the lower crossbar of the rear U-shaped frame member 82. In the embodiment shown, the resistance generator 74 is in the form of an eddy current brake that includes a housing in which the mechanics and electronics for the eddy current brake are located. A shaft 76 extends from the resistance generator 74 and is operatively coupled thereto. The shaft 76 is rotatably mounted within opposing bearings (hidden in FIG. 1) in the arms of a support bracket 88. The support bracket 88 is, in turn, attached to the rear U-shaped frame member 82 so that the rear wheel 46 contacts the shaft 76 and causes the shaft to rotate as the rear wheel 146 rotates.

Still referring to FIG. 1, a computing device 90, which may be in the form of a bicycle computer, a microprocessor, a programmable circuitry, or the like, may be secured to or otherwise associated with the bicycle 26. In one embodiment, the computing device 90 is secured to the bicycle in a suitable location, such as to the handlebar 38. The computing device 90 may include a memory for storing information pertaining to one or more operating characteristics of the bicycle 26, such as elapsed time, speed, distance, etc., and an optional display for conveying relevant information to the user during operation of the bicycle 26. In the embodiment shown, the computing device 90 may also be connected to an electric drive circuit of the eddy current brake for energizing the electromagnets of the eddy current brake at predetermined times and power levels in order to simulate changes in terrain. Alternatively, the computing device 90 can be centralized and/or located remote from the exercise device 24, and in one embodiment shown in FIG. 4, is capable of supporting a multi-rider environment via suitable software, such as those commercially available from Racermate, Inc., Seattle, Wash. In such an embodiment, a display 92 may be associated with each exercise device for conveying operational information of the associated exercise device and/or operational information from one or more of the other exercise devices in the multi-rider environment.

FIG. 1 further illustrates a cadence sensor 22 that is positioned on a support surface, such as the floor, below one of the bicycle pedals, such as left pedal 58. The cadence sensor 22 is configured to sense each revolution of the pedal 58, and generate signals indicative thereof. The generated signals can be outputted to the computing device 90 for processing, display, etc. The signals generated by the cadence sensor 22 can be subsequently utilized by the computing device 90 to calculate the number of pedal strokes per minute or revolutions per minute (RPMs) of the pedals. It will be appreciated that the revolutions per minute (RPMs) of the pedals can be calculated by known techniques in the art. In that regard, in one embodiment, the computing device 90 may include a timer for keeping time, and a counter for tracking the number of signals generated by the cadence sensor 22 over a period of time. The computing device 90 may then calculate the pedal revolutions per minute (RPMs) by taking the number of signals generated by the cadence sensor 22 and dividing that by the period of time over which the signals where counted. The period of time, for example, can be a minute (i.e., 60 seconds) or any fraction of a minute (e.g., ¼, 1/10, 1/20, 1/30, 1/60, etc.).

In other embodiments, the cadence sensor 22 may be configured to accumulate the number of instances the component of the drivetrain is detected over a predetermined period of time. The cadence sensor 22 may be further configured to transmit the accumulated signals to the computing device at a determined time interval for further processing. In some embodiments, the cadence sensor 22 may also include circuitry to process the signals indicative of each revolution of the pedal 58, and to calculate the current cadence associated with the exercise device.

Turning now to FIGS. 2A-2B, there is shown a cross sectional view of one example of the cadence sensor 22 formed in accordance with aspects of the present disclosure. As best shown in FIG. 2A, the cadence sensor 22 generally includes a sensor 96 mounted, for example, within a protective enclosure 98. Generally described, the cadence sensor 22 acts as a proximity sensor or switch that generates a signal upon detection of a target, such as the pedal 58, and as such, generates a signal for each revolution of the pedal.

In the embodiment shown in FIG. 3, the sensor 96 comprises an emitter 102, a detector 104, and associated device circuitry 106. The emitter 102, such as an LED, emits a beam of light 110 (See FIGS. 2A and 2B), such as infrared light, at a high speed, under control of the device circuitry 106. On the other hand, the detector 104, such as a photodiode or the like, senses any of the emitted beams of light 110 that was reflected off the target, such as the bicycle pedal 58, referred herein as “reflected light 114.” In response to the reception of reflected light 114 (See FIG. 2B), the detector 104 and/or device circuitry 106 generates a signal for output via a communication link, such as signal cable 116, to the computing device 90 or the like. In the embodiment shown in FIGS. 2A and 2B, the enclosure 98 includes a base 124 detachably connected to a lid or cover 128 via any fastening technique that provides a secure coupling between the base and the cover 128 when connected thereto but also provides selective decoupling for separating the base and the cover. One such fastening technique that may be practiced with embodiments of the present invention is a threaded connection, as shown in FIGS. 2A and 2B. The sensor 96 is mounted on a planar surface of the base 124, such as upon boss 130, and aligned below a centralized opening or window 132 in the cover 128. A protective lens 138 is positioned over the sensor 96 and aligned with the opening 132 of the cover 128 between the base 124 and the cover 128. In the embodiment shown, the lens 138 and the boss 130 of the base 124 cooperate to ensconce the sensor 96. The lens 138 can be made of glass, plastic, etc., and is translucent or transparent such that the beam of light emitted from the sensor 96 (via emitter 102) can pass through the window portion 140 of the lens 138 to the exterior of the enclosure 98 a predetermined distance, thereby defining the nominal range of the cadence sensor 22 and shown as by the arrow 144 in FIG. 2B, and similarly, reflected light 114 of a suitable intensity, which has been reflected by the target, can pass back through the lens 138 and be detected by the sensor 96 (via detector 104). A seal 146 may be provided between the cover 128 and the protective lens 138 in order to keep dirt and other debris from the sensor 96.

In one embodiment, the lens 138 is dome shaped and is constructed out of transparent glass. In this embodiment, the lens 138 is of suitable thickness to provide compression strength to withstand the force of a rider's foot stepping or falling onto the sensor 22.

The operation of one embodiment of the cadence detection system 20 in accordance with aspects of the present disclosure will now be described in detail. In operation, the rider rotates the pedals of the bicycle 26, which in turn, drives the rear wheel 46 against the shaft 76, which in turn, rotates against the resistance generated by the resistance generator 74. In some embodiments, as the rider turns the pedals, the computing device 90 outputs commands to the resistance generator. These commands can, for example, instruct the resistance generator to energize the load generator, such as an eddy brake, at predetermined times and power levels in order to simulate changes in terrain.

During use of the exercise device 24, the cadence sensor 22 detects the rotation of the drivetrain 28, and if desired, calculates the cadence of the rider in real-time or near real-time (e.g., rolling increment of 1 second, 5 seconds, etc.). In that regard, the device circuitry 106 drives the emitter 102 to emit a beam of light 110, such as infrared light, at high speed. The beam of light 114 emitted from the emitter 102 passes through the lens 138 and out through the opening 132 of the cover 128 to the nominal range 144 of the cadence sensor 22. With every revolution of, for example, the left pedal 58, the pedal passes through the nominal range 144 of the cadence sensor 22. As it passes through the nominal range of the cadence sensor 22, the beam of light 110 emitted from the emitter 102 reflects off of the pedal 58 as reflected light 114 back toward the detector 104. The detector 104 then detects the reflected light 114, and in response to the detection of the reflected light 114, the device circuitry 106 and/or the detector 104 generates a signal for output via a communication link, such as signal cable 116. In this way, the cadence sensor 22 generates a signal for each revolution of the pedal 58. The generated signals can be transmitted to computing device 90 or the like and utilized thereby for calculating the number of pedal strokes per minute or revolutions per minute (RPMs) of the pedals. In one embodiment, the cadence sensor 22 is arranged and configured such that a signal is generated when the pedal 58 is positioned at its maximum or lowest position during its down stroke.

While the system 20 has be shown herein and described above with a bicycle/trainer combination as the exercise device, other pedal powered exercise devices and non-pedal powered exercise devices may also be employed. For example, a cadence detection system 220, 320 may be comprised of an upright type or recumbent style stationary bicycle 224, 324, respectively, and the cadence sensor 22, as best shown in FIGS. 5 and 6. Additionally, a cadence detection system 420 may be comprised of a cross country skiing trainer 424 and the cadence sensor 22, as best shown in FIG. 7. Other non-pedal powered exercise devices may also be employed in embodiments of the present disclosure, such as stair stepping machines, rowing machines etc.

Various principles, representative embodiments, and modes of operation of the present disclosure have been described in the foregoing description. However, aspects of the present disclosure which are intended to be protected are not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. It will be appreciated that variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present disclosure. Accordingly, it is expressly intended that all such variations, changes, and equivalents fall within the spirit and scope of the claimed subject matter. 

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
 1. A cadence detection system for use during exercise, comprising: an exercise device having a moveable drivetrain configured to provide a cadence, the moveable drivetrain including a target surface; an optical sensor placed on a surface separate from the exercise device and positioned in optical view of the target surface of the moveable drivetrain, the optical sensor including an emitter configured to generate an optical signal for output and a detector configured to detect the optical signal after reflection off of the target surface, wherein the optical sensor is configured to generate an electrical signal based on the detected optical signal; and a computing device configured to receive the electrical signal from the optical sensor and to calculate at least detected optical sensor signal instances received per unit of time.
 2. The cadence detection system of claim 1, wherein: the emitter has a nominal range; the drivetrain includes a pedal with the target surface thereon and having a pedal stroke; and the target surface of the pedal enters the nominal range at the maximum position of the pedal stroke.
 3. The cadence detection system of claim 2, wherein the maximum position of the pedal stoke occurs at a position closest to the optical sensor.
 4. The cadence detection system of claim 1, wherein the emitter of the optical sensor uses an LED light source, wherein the LED light source emits one of infrared and visible light.
 5. The cadence detection system of claim 1, wherein the surface separate from the exercise device is a substantially horizontal surface that supports the exercise device.
 6. The cadence detection system of claim 1, wherein the computing device includes a display to convey information to a user during operation of the exercise device.
 7. The cadence detection system of claim 1, wherein the computing device is mounted to the exercise device.
 8. The cadence detection system of claim 1, wherein the computing device is capable of simultaneously supporting two or more optical sensors, each optical sensor associated with a discrete exercise device.
 9. The cadence detection system of claim 1, wherein the exercise device includes one of an upright stationary bike, an indoor cycle trainer, a bicycle trainer, a recumbent stationary bike, an elliptical trainer, and a cross country skiing trainer.
 10. The cadence detection system of claim 1, wherein the target surface is at least a part of a pedal or a crankset.
 11. A cadence detection system for use during exercise, comprising: at least two exercise devices having moveable drivetrains, each configured to generate a unique cadence, the moveable drivetrains each including a target surface; an optical sensor associated with each exercise device and placed on a surface separate from the associated exercise device, each optical sensor positioned in optical view of the target surface of the respective moveable drivetrain, wherein each of the optical sensors includes an emitter configured to generate optical signals for output and a detector configured to detect the optical signals after reflection off of the respective target surface, wherein each of the optical sensors are configured to generate electrical signals based on the detected optical signals; and a computing device configured to receive the electrical signals from the optical sensors and to calculate at least detected optical sensor signal instances received per unit time.
 12. The cadence detection system of claim 11, further comprising a display associated with each exercise device, wherein each display is configured to convey information to a user during operation of the exercise device.
 13. The cadence detection system of claim 12, wherein the information conveyed to the user by the display corresponds to one or more operational parameters of the exercise device associated with the display.
 14. The cadence detection system of claim 13, wherein the information conveyed to the user by the display corresponds to one or more operational parameters of an exercise device associated with a different display and at least one additional user.
 15. The cadence detection system of claim 12, wherein the at least two exercise devices are substantially similar and selected from the group consisting of an upright stationary bike, an indoor cycle trainer, a bicycle trainer, a recumbent stationary bike, an elliptical trainer, and a cross country skiing trainer.
 16. A method of detecting cadence during stationary exercise, comprising: continuously emitting light from a light source having a nominal range; moving a component of a drivetrain into and out of the nominal range; detecting reflected light off of the component; and calculating cadence of the drivetrain.
 17. The method of claim 16, wherein the component of the drivetrain enters the nominal range at the maximum stroke position of the drivetrain.
 18. The method of claim 17, wherein the optical sensor is configured to send the signal to the computing device each time the component is detected.
 19. The method of claim 17, wherein the optical sensor is configured to send the signal to the computing device at a determined time interval, the signal transmitting the number of instances the component is detected during said time interval.
 20. The method of claim 17, wherein the computing device displays information associated with operation of the exercise device to a user. 